Bass Rolloff VS Bass Cutoff

  • Thread starter Thread starter Smokepole
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Smokepole

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I purchased a Shure KSM27 as my first mic. The directions are vague as when to use cutoff or rolloff. I'm a beginner. I understand that there is no one way or right way rule from reading posts. However can you give me some basic dos and don'ts as to when to use which?

I read the thread on rolloff and now understand why I would want to eliminate unwanted freq. from the start.

I will be using the mic for vocals, acoustic guitar.
The manual reads;
Cutoff- 18db per octave at 80 Hz.
Rolloff- 6db per octave at 115Hz.

Thanks in advance
 
"Cutoff- 18db per octave at 80 Hz."

You would use this to eliminate unwanted rumble and any low frequency stuff getting into the mic. It cuts off all the deep bass completely.

"Rolloff- 6db per octave at 115Hz."

This is for eliminating the proximity effect when singing in close to the mic (under 6" away).
 
Thanks Harvey pleased to meet you.

That helps for a basic guideline. So I would use that setting on vocals within in 6" of the mic. They should clarify that in the directions.

What about with the acoustic though? I only ask because the other post I read seemed adamant about using these options on almost everything except bass, Kick drums, and recordings of earthquakes.
 
Well, a guitar doesn't have much energy at 80Hz, so you might as well use the cutoff on it, and violins, and flutes, and, and.... about anything that doesn't have a lot of low end, since you may not hear low thumps till it's too late. Bumping a mic stand will put out a low frequency thump that can ruin an otherwise good take, and it's hard to eliminate after the fact.
 
Thanks, That's just what I wanted. Some very basic guidelines to begin with.

Have a good night
Joe
 
Yes! Yes, let's all have a good night!

God bless us....everyone!
-kent
 
Checking, test, check one, testing. Can you hear me out there?

I just tried my new mic and wanted to puke. (what a lousy feeling)

I'm hoping it's not the mic though. I borrowed a little preamp because I needed phantom power and it seems really noisy. Poor quality, hissy noise all around. It seemed to boost the signal but it was truly ugly. Bellari MP105

Is there an alternative to get phantom power to the mic?

I'm a beginner but I hate what I heard. My 25-year-old SM58 sounds like a million dollars compared to this side by side. And that's been used for everything short of a hammer!

I'm heading off to Guitar center in a couple of hours, I think they may have a return policy so I can try a different preamp or something. I'm going to see if I can get some help.

I figured I would post this in the meantime to see if anyone had any suggestions.

Signed
The depressed rookie
 
I would go for an audio buddy ($79) or if they have one, a DMP3 (around $150, I believe)..... these are both great little no-frills two channel preamps made by M-Audio.....
 
What's the Frequency?

The fundamental of the lowest note on a 6-string guitar in standard (A=440) tuning is, in fact 82.41 Hz. And if you can sing that low, you might find work saying "This is CNN."
 
Thanks for the reply. I almost ordered one of the audio buddies last week but the guy at my local music store who does the ordering was out. It seems to be highly recommended on other sights also.

I came home from G.C. with a dbx ProVocal.

It's really a lot more than I need, but the guy said I could return it for any reason within 30 days. My main concern was to try my new mic again to make sure that wasn't the problem, it wasn't

That preamp must have been defective or something. Nobody would like the quality of the recording I was getting.

This dbx is tempting. For a rookie, the presets are great. However my little recorder (VS840EX) already has some multi effect vocal preset stuff.

Would the quality be that much better? I haven't had the the system recording with a mic yet other than a few tests.

Anybody with any thoughts feel free to chime in.
 
Re: What's the Frequency?

sjjohnston said:
The fundamental of the lowest note on a 6-string guitar in standard (A=440) tuning is, in fact 82.41 Hz.
Click to expand...
While that's true, there's not a whole lot of fundamental there, since a guitar string's length is smaller than 1/4 wavelength (an 82 Hz note is about 14 feet long), so you get a lot of 164 Hz and 328 Hz overtones instead.
 
It's good you you returned the Bellari MP105, as it's an
awful mic pre. One other buyer, (besides me) called it the
"hum injector", and also returned it.

Chris
 
Wait a minute!
On second thought it must be the microphone.
I'll give you 50 bucks CASH right now to rid you of the problem,
and take that lousy Shure mike!

Chris
 
Harvey Gerst said:
"Cutoff- 18db per octave at 80 Hz."
You would use this to eliminate unwanted rumble and any low frequency stuff getting into the mic. It cuts off all the deep bass completely.

"Rolloff- 6db per octave at 115Hz."
This is for eliminating the proximity effect when singing in close to the mic (under 6" away).
Click to expand...
I should add a few things to this statement that might not be readily apparent:

When a manufacturer specifies a particular roll off frequency, it doesn't mean that's where the roll off starts; it's usually the frequency where the signal is down by a certain level already, usually, the 1/2 power point.

That means the signal for the 80 Hz roll off is starting to drop at around 150Hz, and the 115 Hz rolloff is already starting to rolloff around 300 Hz.
 
chessparov said:
Wait a minute!
On second thought it must be the microphone.
I'll give you 50 bucks CASH right now to rid you of the problem,
and take that lousy Shure mike!

Chris
Click to expand...

that's messed up chess...... no need to exploit the guy's vulnerability........ ;)
 
Thanks guys for all the info, I'm taking notes

Harvey, trying to play with this preamp I bumped the mic stand like you warned but it wasn’t real apparent on the track. I see what you mean. It worked nicely.

chess, seriously how could anyone use that preamp? It was really bad. No wonder the guy who let me borrow it replaced it immediately with something better. It's still sitting here because I got that from a friend. (I hope it doesn't cause me to have nightmares tonight) that was scary!

My local music store (not G.C.) gave me that mic for $260. I'm very satisfied with it. I think the rolloff and cutoff are going to be a nice feature for home recording. I would want at least $80 for it . What do you take me for, an idiot?
 
Re: Re: What's the Frequency?

Harvey Gerst said:
While that's true, there's not a whole lot of fundamental there, since a guitar string's length is smaller than 1/4 wavelength (an 82 Hz note is about 14 feet long), so you get a lot of 164 Hz and 328 Hz overtones instead.
Click to expand...

My main point was really that cutting below 80 Hz couldn't do a lot of damage, since a normal guitar can't really be made to produce musical-type sounds below that, but ... this intrigues me.

The wavelength of an 82 Hz note is something around 14 feet long in the air, but I'm not sure I understand the relationship between the string length and the length of the wave in air. Then again, there's a lot I don't understand.
 
This gets a little tricky to explain, and I'm not sure I wanna make this another "big thread". I'd hafta explain about horn theory, low efficency speakers, cutoff points and a whole lot of complex other stuff that would come up because of an oversimplification. Give me a little while to think about how to explain it simply but clearly.

For right now, think about the difference in size between a double bass, a cello, and a violin, and the frequency range each instrument covers. Also consider a real pipe organ, and the various sizes and lengths of pipes in each rank. Think about the different string lengths and string thicknesses in a grand piano.

Where's Don Herbert ("Mr. Wizard") when you really need him?
 
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